The study of long-term variation in physiological cardiopulmonary rhythms in mice is rapidly expanding. The reason is that there are an ever-increasing number of strains of mice that have been genetically engineered to test scientific hypotheses about the molecular mechanisms of the cellular processes that control these biological rhythms. Since mice are so small, conventional recording systems need significant modification (indwelling vascular catheters) or are not applicable at all (skin electrodes). The development of a non-invasive sensor system for the continuous and reliable monitoring of respiratory rate, HR, and possibly blood pressure trends in mice is proposed. The sensor is based on a fiber-optic coupler sensor technology that has proven its applicability to physiological monitoring in humans in a number of applications. The sensor technology, which showed promising results in preliminary experiments, is very sensitive and scalable in size. The design of the sensor system, once it has been optimized using a "synthetic" mouse, will be tested on 8-10 mice that have been fitted with an EKG monitoring system commonly used in the mouse research community. The data will be analyzed and the reliability of the approach assessed using different algorithms, including wavelet transforms.